To provide a hot water storage type hot water supply apparatus capable of positively impeding breaking of an interface between hot water and water in an oblong hot water storage tank.

This hot water storage type hot water supply apparatus is provided with the oblong hot water storage tank 4 for storing hot and cold water with a water supply pipe 7 and a hot water discharge pipe 5 connected thereto, and a heating means 2 for heating hot and cold water in the hot water storage tank 4. The bottom part of the hot water storage tank 4 is provided with a water supply auxiliary pipe 9 longitudinally extended communicating with the water supply pipe 7 and provided below with a plurality of water supply holes 12 formed of small holes. Since the water supply pipe 7 and water supply auxiliary pipe 9 are communicated through a communicating pipe 13 fixed to the hot water storage tank 4, the interface between hot water and water is kept well without breaking, and the supply of stored high temperature water can be carried out to the last. Since the water supply pipe and water supply auxiliary pipe are communicated through the communicating pipe welded beforehand to the hot water storage tank, communication is achieved only by screwing without needing new welding work. Assembly work is thereby facilitated while having no anxiety about a water leak after work.